VBM brewing group must be considered as the alter ego of Faema historical group; both conceived by Carlo Ernest Valente, they can be considered as twins.
The intuitions providing the guidelines for VBM-E61 project went together with the principles of the first mathematical models about espresso process, even now considered the golden rule for the perfect Italian Espresso: to get a certain volume of drink (30 ml), in a certaine time (30 seconds), with certain temperatures/pressures values (90 °/9bar), by grinding and pressing (20 kgf) a certain quantity of coffee powder (6,5 gr.).
Among all intuitions making VBM-E61 group the most popular brewing system, there were:
THERMOSIPHONIC CIRCULATION principle:
allowing a more precise temperatures control while coffe is in the group.
MECHANIC PRE-INFUSION principle:
so that coffee ground get wet just before the extraction, amplifying in this way both body and flowery taste of coffee.
VBM-E61 group never changed throughout its history; anyway the more and more precise determination of the espresso variables values, the growing availability of scientific data on coffee, the using of electronic controls of temperatures/pressures and the instant electronic grinding will of course require some updating to the project, despite its incomparable intuition.
HX TECHNOLOGY (Heater eXchanger)
Heat Exchanger technology, based on thermosyphonic circulation principle, can be considered the most popular system in the world of espresso coffee machines.
As described in the graph, the parts involved in this technology are:
Boiler (B) with inner vertically welded tube (one for each group) also called heat exchangers (HX).
Brewing group (GH).
Upper circulation tube (IT) it brings water from the boiler exchanger (HX) to the brewing group.
Lower circulation tube (OT) it brings water from the brewing group to the boiler exchanger.
Boiler volume (B), made up of hot water and steam in varying proportions, besides supplying steam and hot water for tea production, also warms the heat exchanger sides (HX) where water going towards the brewing group (GH) is passing inside the upper circulation tube (IT): longer the time water is in contact with the exchanger sides (HX), highest will be water temperature entering the brewing group (GH).
Since the brewing group ( GH) is a metal body with very lower temperatures compared to water entering the group, the same water will transfer heat to the metal when in touch with the group and, once cooled down ( and so heavier) will go down to the bottom part of the group. From here, water is conveyed inside the lower circulation tube (OT) and put again in the heat exchanger (HX) inside the boiler (B).Water circulation has then the following functions:
- To keep the group body hot during idle phase.
- To make espresso when the hydraulic circuit of the group is open.
Water temperature while entering the group (GH) can be changed, besides the adjustment of boiler pressure (B) through:
- Length of injectors (I) bringing water inside the exchanger (HX):
longer the injector, shorter the time water is in contact with exchanger walls (HX), colder the water temperature entering the group ( GH) and e vice versa.
- Restrictors positioning (R) inside upper and lower circulation tubes (IT and OT):
the decrease in water rate of flow causes a decrease in the group heating up (GH); a colder temperature of water coming from the boiler (B) through the lower circulation tube (T) makes water temperature inside the boiler drop.
During the idle phase circulation is carried out through water moving down (water cooling) and up (water heating) inside hydraulic circuit : this is the convection current.
While the machine is brewing coffee, circulation is carried out through pump pressure (9 bar approx.): a bigger pressure is needed to win the strength of coffee powder, which is not necessary during the idle phase.
SMALL OVERALL DIMENSIONS: 25 x 45 x 42 cm
CHROME OUTER TAPS WITH SCREW CONTROL
360° ADJUSTABLE STAINLESS STEEL STEAM LANCES
2 HOLES STEAM LANCE END: 1,5MM DIAMETER; 30° INCLINATION
STEAM BOILER 1.1L
POWER OF ELEMENT 1600W
NUMBER OF PORTAFILTERS: 2
SPOUT TYPE: SINGLE & DOUBLE
BASKET DIAMETER: 58mm
OPERATING PRESSURE: 8-9 BAR
MANUAL PRESS REGULATION
PRESSURE RELIEF VALVE
BOILER TYPE: NICKEL PLATED COPPER
NUMBER OF BOILERS: 1
BREW GROUP MATERIAL: CHROME BRASS
WATER TANK CAPACITY: 1.7L
TANK REMOVAL: YES
ABLE TO PLUMB IN EXTERNALLY: NO
TANK MATERIAL: PLASTIC
CONSTRUCTION: STAINLESS STEEL
CHROME OUTER TAPS WITH SCREW CONTROL
WARRANTY: 12 months back to base